According to SNT-TC-1A (2020), when a new technique is added to the employer's written practice, the NDT Level III personnel:

may be “grandfathered” into the technique.

should first meet the requirements of Level II before being certified as a Level III in the new technique.

should be qualified to the new technique in accordance with the employer’s written practice.

should receive applicable training, take applicable examinations, and obtain the necessary experience, such that the NDT Level III meets the requirements of the new techniques in Table 6.3.1A, prior to their next recertification date, in the applicable method.